Why does the contact list field have a limit?


I have a contact list field that I use on a form. The list has 90 contacts, but in the sheet only 50 values are available.

Why is this? This value is almost always populated from the form, which is good, but sometimes I need to change the value in the sheet, and if I need to change to a name beyond the limit, I have to add new. And in order to do that, I have take off the restriction that the field is only values from the list.